International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part Bl. Istanbul 2004 
  
nbul 2004 
d sampl for a complete set of angular measurements we obtain an Illumination zenith angle - 30 - PBU4 
3 € 
    
    
ce which experimental estimate of the target directional-hemispherical 000 
reflectance Pexp(4.90>H9:27,) - The ratio between this two di 
rence and estimates is related to the constant a . S50 
executed | 
s $,) for 4. PRELIMINARY RESULTS 5 
£ 
» ) for the A first set of measurements have been performed using a g me 
spectral sample of sand (PBU4) with grain size of 0.4-0.6 mm. ë eo 
= 180 Measurements were performed placing both the illuminating 200 
Fi HOST and viewing fiber on the same azimuthal plane and varying the 35.0. 
lirectional viewing angle after having fixed the source zenith angle. 30.0| 
the flux In Figures 3-6 reflectance contour plots versus wavelengths and 25.0 3 
20.0 = “ee, == A EN 208 EN 
0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 
wavelength (micron) 
viewing zenith angles are reported for an illumination zenith 
into the 
Le angle of 0°. 15°, 30°; and 45°. 
Illumination zenith angle = 0 - PBU4 
Figure 5. Reflectance contour plots for PBU4 sand versus 
   
  
  
80.0 Js ; ais P 
| viewing zenith angles and wavelengths for illumination zenith 
75.01 = 0 
Ant A ; angle 6; = 30° degree. 
9,AQ, (5) Zoi 
Illumination zenith angle = 45 - PBU4 
65.0 80.0 : - 
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ted with a € 550 
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35.0 z 
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sopP m BS ltl FE 
0.40 0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 
3, AQ, wavelength (micron) 
Toi A03 
9o A ; S 
$6.50, Figure 3. Reflectance contour plots for PBU4 sand versus : 
viewing zenith angles and wavelengths for illumination zenith "iat 50 55 DES 050055 0700.75 060 0.65.0930 0.05 100 
> 
angle 6; = 0° degree. wavelength (micron) 
‘ways was 
ployed to Illumination zenith angle = 15 - PBU4 Figure 6. Reflectance contour plots for PBU4 sand versus 
We point en viewing zenith angles and wavelengths for illumination zenith 
y S(X) is angle 0; = 45° degree. 
¢,) from 
; ; Figure 7 and Figure 8 show bi-directional reflectance versus 
plained in T pe ; »p Y. ] 
et-up the illumination and viewing zenith angles for two wavelengths (0.5 
set- : 
ièthe + um and 0.8 um). 
eflectance 
Wavelngth = 0.5 micron - PBU4 
1e product 80.0: = - ri ——— 
  
    
   
View zenith angle 
lirectional 
je target 
istribution 
    
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wavelength (micron) N 
z 
o 
s9 7 2 ; | 5 
s O Figure 4. Reflectance contour plots for PBU4 sand versus 
viewing zenith angles and wavelengths for illumination zenith -10.0 ES 
angle 0; = 15° degree. -20.0 
-30.0 
we have me 
ispherical 4000 100 200 300 400 500 600 700 
Illumination Zenith Angle 
r Lambda 
ultraviolet Figure 7. Contour plot of directional reflectance versus 
ium lamp illumination and viewing angles at 0.5 pm for PBU4 sand. 
ind SWIR 
cally Eq.7